Space cabin atmospheres

Space cabin atmospheres - physical and physiological variable

Microwave radiation

Physiological effects of microwave radiation on animals and humans and establishment of human tolerance limit

Improved Nearly-MDS Expander Codes

A construction of expander codes is presented with the following three properties: (i) the codes lie close to the Singleton bound, (ii) they can be encoded in time complexity that is linear in their code length, and (iii) they have a linear-time bounded-distance decoder. By using a version of the decoder that corrects also erasures, the codes can replace MDS outer codes in concatenated constructions, thus resulting in linear-time encodable and decodable codes that approach the Zyablov bound or the capacity of memoryless channels. The presented construction improves on an earlier result by Guruswami and Indyk in that any rate and relative minimum distance that lies below the Singleton bound is attainable for a significantly smaller alphabet size.Comment: Part of this work was presented at the 2004 IEEE Int'l Symposium on Information Theory (ISIT'2004), Chicago, Illinois (June 2004). This work was submitted to IEEE Transactions on Information Theory on January 21, 2005. To appear in IEEE Transactions on Information Theory, August 2006. 12 page

Response of Bose gases in time-dependent optical superlattices

The dynamic response of ultracold Bose gases in one-dimensional optical lattices and superlattices is investigated based on exact numerical time evolutions in the framework of the Bose-Hubbard model. The system is excited by a temporal amplitude modulation of the lattice potential, as it was done in recent experiments. For regular lattice potentials, the dynamic signatures of the superfluid to Mott-insulator transition are studied and the position and the fine-structure of the resonances is explained by a linear response analysis. Using direct simulations and the perturbative analysis it is shown that in the presence of a two-colour superlattice the excitation spectrum changes significantly when going from the homogeneous Mott-insulator the quasi Bose-glass phase. A characteristic and experimentally accessible signature for the quasi Bose-glass is the appearance of low-lying resonances and a suppression of the dominant resonance of the Mott-insulator phase.Comment: 20 pages, 9 figures; added references and corrected typo

Effect of hybridization on the magnetic properties of correlated two-band metals

The magnetic properties of transition-like metals are discussed within the single site approximation, which is a picture to take into account electron correlations. The metal is described by two hybridized bands one of which includes Coulomb correlation. The presented results indicate that ferromagnetism arises for adequate values of hybridization (V), correlation (U) and occupation number($n_{\sigma}$). Some similarities with Dynamical Mean-Field Theory (DMFT) are indicated.Comment: 3 pages, 3 figures, presented at the 53rd MMM08 conference in Austin, 200

Intercontinental clock synchronization with the block 1 VLBI system

The Block 1 very long baseline interferometer (VLBI) operated by the Deep Space Network (DSN) to make weekly measurements of the relative epoch and rate offsets between the time standards in the global network of DSN stations is discussed. The precision of these measurements routinely achieves sub-microsecond levels for epoch offset and accuracies of better than one part in 10 to the 12th power for rate offset. The implementation of the phase calibrator system permits absolute measurement of epoch offset to better than 10 nanoseconds. With the near-real-time play-back and on-line storage of VLBI data, the Block 1 system typically produces clock parameters within 48 hours from the time of observation